title: The competency of pars plana vitrectomy incisions: a comparative histologic and spectrophotometric analysis.
abstract: OBJECTIVE
  To compare the relative competency of pars plana vitrectomy (PPV) sclerotomies.
  
  
  METHODS
  Laboratory investigation.
  
  
  METHODS
  PPV was performed in human cadaveric eyes using 20-gauge (20 G), 23-gauge (23 G), and 25-gauge (25 G) instrumentation. India ink was applied over a sclerotomy site while the intraocular pressure was varied. The presence of India ink particles (IIPs) along incisions was evaluated by histologic analysis. Spectrophotometric absorbance levels of vitreous aspirates were measured.
  
  
  RESULTS
  PPV was performed in a control eye and two eyes, each using standard 20 G, standard 23 G, perpendicular 25 G, and beveled 25 G instrumentation incisions. IIPs were not detected in the 20 G incisions either on histology or by spectrophotometry. IIPs were detected along the entire incision length in one of two eyes with 23 G sclerotomies and confirmed by spectrophotometry. IIPs were detected along the entire incision length in one of two eyes with 25 G perpendicular sclerotomies and confirmed by spectrophotometry in both eyes. IIPs were noted partially along the length in one of the two beveled 25 G eyes, but not detected in either eye by spectrophotometry.
  
  
  CONCLUSIONS
  During the early postoperative period, sutureless vitrectomy incisions may allow entry of ocular surface fluid. These findings may provide a pathophysiologic mechanism for the reported increased risk of endophthalmitis in small-gauge vitrectomy surgery.
authors.affiliation: Retina Service, Wills Eye Institute, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
authors.forename: Omesh P
authors.initials: OP
authors.lastname: Gupta
authors.forename: Joseph I
authors.initials: JI
authors.lastname: Maguire
authors.forename: Ralph C
authors.initials: RC
authors.lastname: Eagle
authors.forename: Sunir J
authors.initials: SJ
authors.lastname: Garg
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Gonye
mesh_terms: D000867:Anterior Chamber / Q000378:metabolism*; D002244:Carbon / Q000493:pharmacokinetics*; D006801:Humans; D007281:Ink; D007429:Intraocular Pressure / Q000502:physiology; D008866:Microsurgery; D012590:Sclera / Q000378:metabolism* / Q000601:surgery; D012599:Sclerostomy; D013056:Spectrophotometry, Ultraviolet; D013529:Surgical Wound Dehiscence / Q000378:metabolism*; D013537:Sutures; D014821:Vitrectomy; D014822:Vitreous Body / Q000378:metabolism*; D014945:Wound Healing / Q000502:physiology
chemical_list: C028433:chinese ink; D002244:Carbon